Hydrogels with amphiphilic chains and targeted adhesion for high-areal-capacity zinc batteries

Two impending problems of practical rechargeable aqueous zinc metal batteries (RZMBs) are the underutilization of high-loading materials at the cathode side and zinc dendrite at the anode side. Herein, based on hydrophobic association, we report the amphiphilic hydrogel electrolytes featured by unique hydrophobic association and target permeation properties, which enables full utilization of dense thick cathode materials with loading masses approaching a practical level. Meanwhile, the ion tunnels within the amphiphilic hydrogel electrolytes can regulate Zn2+ migration and homogenize interfacial deposition at different current densities, rendering a smooth and compact Zn morphology in a dendrite- and passivation-free manner. Meriting these advantages of the amphiphilic hydrogel electrolytes, the assembled Zn||MnO2 batteries delivered a high areal capacity of >2.0 mAh cm-2 for 200 cycles at a large MnO2 loading mass up to 16.8 mg cm � 2. Further, large-sized (up to 200 cm � 2) Zn||MnO2 pouch batteries were demonstrated. This work opens a new avenue toward realizing viable RZMBs with practical large areal capacities and sizes.

Automated summary

This study addresses two challenges in practical rechargeable aqueous zinc metal batteries (RZMBs), namely the limited utilization of high-loading materials at the cathode and the formation of zinc dendrites at the anode. By using hydrophobic association, the researchers have developed amphiphilic hydrogel electrolytes with unique properties that enable full utilization of high-loading cathode materials and prevent dendrite formation. The use of these electrolytes in Zn||MnO2 batteries has resulted in high areal capacities and the demonstration of large-sized pouch batteries. This work opens up new possibilities for practical RZMBs with large capacities and sizes.